CPC G01R 27/2688 (2013.01) [G01R 31/3004 (2013.01); G06F 1/30 (2013.01); G11C 29/02 (2013.01)]  20 Claims 
1. A method for determining an abnormal leakage current of a capacitor, comprising:
maintaining stored values from leakage current tests of the capacitor in a storage for a maximum upper limit, a minimum upper limit, a maximum lower limit, and a minimum lower limit of leakage current values for the capacitor;
determining, using a test circuit coupled to the capacitor, a number of recent leakage current values for the capacitor;
determining a present upper limit and a present lower limit for the recent leakage current values;
updating the stored value of the maximum upper limit for the capacitor by replacing the maximum upper limit with the present upper limit if the present upper limit is greater than the stored value of the maximum upper limit;
updating the stored value of the minimum upper limit for the capacitor by replacing the minimum upper limit with the present upper limit if the present upper limit is lower than the stored value of the minimum upper limit;
updating the stored value of the maximum lower limit for the capacitor by replacing the maximum lower limit with the present lower limit if the present lower limit is greater than the stored value of the maximum lower limit;
updating the stored value of the minimum lower limit for the capacitor by replacing the minimum lower limit with the present lower limit if the present lower limit is lower than the stored value of the minimum lower limit; and
detecting the abnormal leakage current in response to determining that the present upper limit is greater than an upper threshold or the present lower limit is less than a lower threshold,
wherein the upper threshold is a determined value between the stored values of the maximum upper limit and the minimum upper limit, and the lower threshold is a determined value between the stored values of the maximum lower limit and the minimum lower limit.
